Divert air valve for an internal combustion engine

ABSTRACT

A divert air valve for an internal combustion engine arranged in a bypass channel between a pressure side and a suction side of a supercharging device includes a housing. A bypass valve comprises a first valve closure body. A control pressure chamber is connected with the pressure side through a compensation opening. A solenoid valve comprises a coil body, a magnetic yoke arrangement, an armature, and a second valve closure body which comprises a second spring element and cooperates with the armature. When the solenoid valve is energized and the bypass valve open, a fluidic communication can be established between the pressure side and the suction side or the atmosphere through the control pressure chamber. An overall cross section of the at least one control opening is larger than a cross section of the compensation opening. A closing of the fluidic communication causes a resultant force in a closing direction.

CROSS REFERENCE TO PRIOR APPLICATIONS

This application is a U.S. National Phase application under 35 U.S.C.§371 of International Application No. PCT/EP2011/054301, filed on Mar.22, 2011 and which claims benefit to German Patent Application No. 102010 024 297.7, filed on Jun. 18, 2010. The International Applicationwas published in German on Dec. 22, 2011 as WO 2011/157457 A1 under PCTArticle 21(2).

FIELD

The present invention relates to a divert air valve for an internalcombustion engine, which is arranged in a bypass duct between thepressure side and the suction side of a supercharging device, comprisinga bypass valve with a pneumatically actuable first valve closure bodybiased in the closing direction by a spring force, a control pressurechamber which, in the closed state of the bypass valve, is incommunication with the pressure side via a permanently open compensationopening, and comprising a solenoid valve with a coil body, a magneticyoke arrangement and an armature that is also biased in the closingdirection, as well as a cooperating second valve closure body for atleast one control opening, wherein, by energizing the solenoid valveduring the opening process of the bypass valve, a fluidic communicationbetween the pressure side and the suction side of the superchargingdevice can be established via the control pressure chamber.

BACKGROUND

Divert air valves for the recirculation of compressed combustion gasfrom the pressure side of a compressor of a turbocharger back to thesuction side of the compressor are generally known as divert air valvedevices. The connection between the pressure side and the suction sideof the compressor via a bypass line is required for the transition froma high load to the overrun condition of the internal combustion engine,in order to avoid a high output of the charge pressure pump against aclosed throttle valve and the pump effect resulting therefrom, as wellas an overly strong, abrupt reduction of the turbo speed with theensuing consequences of thermodynamic problems.

Divert air valves are often operated electromagnetically, with the valveclosure body of the valve being moved by the electromagnetic force. Anexample for such an arrangement is described in DE 100 20 041 A1. Thecontrol is effected through a control unit according to available enginedata. The valve comprises a pressure equalization opening at the valveclosure body, whereby a balance of forces is established with respect tothe pneumatic forces, given a corresponding design of the effectivesurfaces. However, these valves have a drawback in that, despite thepressure equalization unit of the valve, a great actuation force isrequired to actuate the valve closure body during the opening, wherelarge solenoids have to be used in particular when the cross sections tobe switched are large. There are at the same time limitations withrespect to the opening times achievable.

In the interest of reducing the necessary magnetic force, DE 102 51 981A1 describes providing a pneumatically actuated divert air valve whosecontrol pressure chamber can be connected with the suction side of thecompressor via a solenoid valve. This leads to the opening of the valve.However, the pressure difference responsible therefor decreases in theopen state, so that an unintentional closing of the valve can occur.

DE 10 2005 028 141 A1 describes a bypass valve for internal combustionengines wherein an opening of the valve closure body is obtained byelectromagnetically lifting a sealing plate from openings via which afluidic communication of the control pressure chamber to the suctionside of the compressor can be established. In addition, a permanentconnection exists between the control pressure chamber and the pressureside via a pressure equalization opening in the valve closure body.However, since the latter has a smaller cross section than the openingsto the suction side, a force acting in the opening direction isgenerated that causes the valve closure body to open. In the open state,however, the valve closure body again abuts against the sealing plate sothat a pressure equilibrium forms at the valve closure body. This maylead to an unintentional closing of the valve due to a spring forceacting in the closing direction. Pressure thereafter builds up again, sothat the valve again opens due to the pressure difference. A controlcircuit comprising a valve that opens and closes is formed, whichresults in increased wear.

SUMMARY

An aspect of the present invention is to provide a divert air valve withwhich the above-mentioned drawbacks can be avoided, a defined positionof the valve closure body provided when the solenoid is activated, whilehaving as simple a structure as possible.

In an embodiment, the present invention provides a divert air valve foran internal combustion engine. The divert air valve is arranged in abypass channel between a pressure side and a suction side of asupercharging device. The divert air valve includes a housing. A bypassvalve comprising a first valve closure body is configured to bepneumatically actuable and to be biased in a closing direction by afirst spring element. A control pressure chamber is, in the closed stateof the bypass valve, connected with the pressure side through acompensation opening which is configured to be permanently open. Asolenoid valve comprises a coil body, a magnetic yoke arrangement, anarmature configured to be biased in the closing direction, and a secondvalve closure body for at least one control opening. The second valveclosure body comprises a second spring element and is configured tocooperate with the armature. When the solenoid valve is in an energizedstate, so that the bypass valve is open, a fluidic communication can beestablished between the pressure side and the suction side of thesupercharging device or the atmosphere through the control pressurechamber. An overall cross section of the at least one control opening islarger than a cross section of the compensation opening, such that, whenthe bypass valve is open, a fluidic communication exists at leasttemporarily between the pressure side and the suction side of thesupercharging device via the control pressure chamber. A closing of thefluidic communication causes a resultant force in a closing direction.

BRIEF DESCRIPTION OF THE DRAWING

The present invention is described in greater detail below on the basisof embodiments and of the drawings in which:

FIG. 1 shows a sectional view of a bypass valve of the presentinvention.

DETAILED DESCRIPTION

By providing a first spring element for the first valve closure body anda second spring element for the second valve closure body, with thetotal cross section of the control opening(s) being larger than thecross section of the compensation opening, it is possible to establish,at least temporarily, a fluidic communication between the pressure sideand the suction side of the supercharging device via the controlpressure chamber when the bypass valve is fully open, wherein a closingof the fluidic communication causes a resulting force in the closingdirection, whereby a defined opening and closing of the bypass valve isachieved. An unintentional closing or pulsating of the valve closurebody is reliably avoided. At the same time, a simple and thus economicstructure of the divert air valve is provided.

In an embodiment of the present invention, the coil body can, forexample, comprise the control opening. This allows for an internal flowthrough the divert air valve. The second spring element mayadvantageously be supported on the magnetic yoke arrangement.

From a manufacturing point of view, it is advantageous if the armatureis formed as a cylinder substantially open at one side, the second valveclosure body being formed at the base of the cylinder. It is alsoadvantageous to provide a solenoid valve housing comprising a fasteningmember arranged in the housing in a sealed manner. The solenoid valvehousing may here be clamped using the fastening member. The first springelement can advantageously be supported at the fastening member.

The fact that the housing comprises a terminating element fixing thesolenoid valve housing in the axial direction allows for a simpleassembly of the divert air valve.

An embodiment is illustrated in the drawing.

The divert air valve 1 of the present invention essentially comprises ahousing 16 in which a bypass valve 2, a solenoid valve 4 and a controlpressure chamber 24 are arranged. Under interposition of a seal 9, thedivert air valve 1 is flanged directly to a channel-forming housing 6 ofa bypass channel 8 non-illustrated supercharger device of an exhaust gasturbo charger, which bypass channel 8 serves as a recirculation channel.The recirculation or bypass channel 8 may be formed either directly inthe housing of the supercharger device or as an external channel.

The bypass valve 2 comprises a pneumatically actuable first valveclosure body 10 that separates a pressure side 12 against which thefirst valve closure body 10 abuts, from a laterally positioned suctionside 14 of the bypass channel 8 of the supercharger device. The firstvalve closure body 10 is biased in the closing direction by means of afirst spring element 18.

In the closed state, a sealing lip 32 of the first valve closure body 10rests on a valve seat 34 formed in the channel-forming housing 6. Thevalve closure body 10 further comprises at least one permanently opendefined compensation opening 36 through which the control pressurechamber 24 is in communication with the pressure side 12, when the valveis in the closed state. As a result, in the closed state, the samepressure acts in the control pressure chamber 16 as on the pressure side12 below the valve closure body 10. In this manner, in the closed state,the bypass valve 2 is substantially balanced with respect to thepneumatic forces. The bypass valve 2 is accordingly maintained in theclosed state by the spring force of the first spring element 18.

In order to also be able to open the bypass valve 2, the housing isfurther provided with the solenoid valve 4 that comprises a coil body20, a magnetic yoke arrangement 22 and an armature 23 also biased in theclosing direction, as well as a second valve closure body 26 for atleast one control opening 38, which cooperates with the armature. In thepresent embodiment, this control opening is provided in the coil body20, the cross section of the control opening 38 being larger than thecross section of the compensation opening 36.

The armature 23 is substantially designed as a cylinder open on oneside, with the second valve closure body 26 being formed at the base 25thereof. A second spring element 27 exerts a spring force in the closingdirection on the armature and thus on the second valve closure body andis supported at the magnetic yoke arrangement of the solenoid valve.

The solenoid valve 4 further comprises a solenoid valve housing 28 withan integrally-connected fastening element 30, which in the presentembodiment is clamped sealingly into the housing 16. The fasteningelement 30 also thus provides the support surface for the first springelement 18. A seal 40 for the first valve closure body 10 is furthersupported in the fastening element 30. The control pressure chamber isaccordingly defined by the interior of the first valve closure body 10,the space between the fastening element 30 and the outer surface of thesolenoid valve housing 28, as well as the interior of the solenoid valve4.

Towards the suction side 14, the housing of the divert air valve 1 isclosed by a termination element 42 which is clamped in the housing 16and fixes the solenoid valve housing 28 in the axial direction. It isalso possible to provide a welding, soldering or other releasable orpermanent connection instead of the clamping connection. The terminationelement 42 has further openings 44 via which, when the second valveclosure body 26 is open, the control pressure chamber 24 is incommunication with the suction side 14 through the control opening 38.

The divert air valve 1 of the present invention operates as follows:

Upon energization of the solenoid valve 4, the armature 23 is movedagainst the closing direction of the second spring element 27, wherebythe control opening 38 is cleared. The gas in the control pressurechamber 24 escapes, since the pressure in the control pressure chamber24 is higher than on the suction side 14 of the supercharging device. Atthe same time, the volume of gas flowing in through the compensationopening 36 is smaller because of the smaller cross section so that apressure drop occurs in the control pressure chamber 24, whereby apressure gradient occurs at the first valve closure body 10 causing aresultant force at the valve closure body 10 in the opening direction ofthe bypass valve 2. The valve closure body 10 is accordingly lifted fromthe valve seat 34 and the bypass valve 2 opens.

If the pressure difference between the pressure side 12 and the suctionside 14 in the recirculation channel 8 subsequently shifts towardspressure equalization, the pressure in the control pressure chamber 24also drops, since gas of lower pressure flows in through the opening 36.However, a pressure gradient always exists in the open state of thesolenoid valve 4 due to the different cross sections of the compensationopening 36 and the control opening 38, which pressure gradient providesthat the bypass valve 2 does not close unintentionally.

When the solenoid valve 4 is again closed, a pressure equalizationoccurs between the bottom side of the first valve closure body 10 andthe control pressure chamber 24. This results in a pneumatic pressureequalization and thus results in a balance of the pneumatic forces. As aconsequence, the bypass valve 2 is closed by the force of the firstspring element 28. This state of pressure balance remains until thecontrol opening 38 is again opened by the solenoid valve 4.

It should be noted that other embodiments of the divert air valve 1 areconceivable without leaving the scope of protection of the main claim.In particular, the control opening 38 can also be connected toatmosphere.

The present invention is not limited to embodiments described herein;reference should be had to the appended claims.

What is claimed is: 1-8. (canceled)
 9. A divert air valve for aninternal combustion engine, the divert air valve being arranged in abypass channel between a pressure side and a suction side of asupercharging device, the divert air valve comprising: a housing; abypass valve comprising a first valve closure body which is configuredto be pneumatically actuable and to be biased in a closing direction bya first spring element; a control pressure chamber which, in the closedstate of the bypass valve, is connected with the pressure side through acompensation opening which is configured to be permanently open; and asolenoid valve comprising a coil body, a magnetic yoke arrangement, anarmature configured to be biased in the closing direction, and a secondvalve closure body for at least one control opening, the second valveclosure body comprising a second spring element and being configured tocooperate with the armature; wherein, when the solenoid valve is in anenergized state so that the bypass valve is open, a fluidiccommunication can be established between the pressure side and thesuction side of the supercharging device or the atmosphere through thecontrol pressure chamber, wherein an overall cross section of the atleast one control opening is larger than a cross section of thecompensation opening, such that, when the bypass valve is open, afluidic communication exists at least temporarily between the pressureside and the suction side of the supercharging device via the controlpressure chamber, whereby a closing of the fluidic communication causesa resultant force in a closing direction.
 10. The divert air valve asrecited in claim 9, wherein the coil body comprises the at least onecontrol opening.
 11. The divert air valve as recited in claim 9, whereinthe second spring element is supported at the magnetic yoke arrangement.12. The divert air valve as recited in claim 9, wherein the armature isprovided substantially as a cylinder which is open on one side and whichcomprises a base, wherein the second valve closure body is formed at thebase.
 13. The divert air valve as recited in claim 9, further comprisinga solenoid valve housing comprising a fastening element, the solenoidvalve housing being arranged in the housing so as to be sealed.
 14. Thedivert air valve as recited in claim 13, wherein fastening element isconfigured to clamp the solenoid valve housing.
 15. The divert air valveas recited in claim 13, wherein the first spring element is configuredto be supported on the fastening element.
 16. The divert air valve asrecited in claim 13, wherein the housing comprises a termination elementconfigured to fix the solenoid valve housing in an axial direction.